Diferentes reguladores de crescimento na indução de calos e pró-embrióides em anteras de cafeeiro

Abstract

The improvement of coffee (Coffea arabica) has been done through conventional methods, which are very cumbersome to obtain the desired genetic material, and this time can be reduced through the acquisition of haploid in segregating generations through the culture of anthers. This study analyzed the effect of growth regulators on C. arabica L. cv. Catuaí Vermelho LCH-2077-2-5-44 anther callus and pro-embryoid induction. First, anther inoculation on MS medium supplemented with 2,4-D (2, 4, 6 or 8 mgL-1), TDZ (0 or 0.5 mgL-1) was evaluated, together with evaluation time (30, 60 or 90 days). The experimental design was as a 4x2x3 factorial in randomized blocks and with four repetitions. Oxidation, intumescences and callosity were evaluated. The use of 2 mgL-1 2,4-D alone was effective for callus induction. High concentrations of 2,4-D inhibited callus formation and the longer the evaluation period, the greater was anther oxidation. Subsequently, the following treatments were evaluated: 2 mg L-1 2,4-D + 2 mg L-1 BAP; 8 mg L-1 Kinetin + 1 mg L-1 AIB; 2 mg L-1 Kinetin + 1 mg L-1 2,4-D; 2 mg L-1 Kinetin + 20 mg L-1 GA3; 2 mg L-1 2,4-D + 0.5 mg L-1 TDZ; 2 mg L-1 ANA or 2 mg L-1 2,4-D. The experimental design was completely randomized, as a 7x2 (regulator composition x in vitro cultivation time) factorial with four replications. After 30 and 60 days in vitrocultivation, contamination, oxidation, intumescences, callus formation with the presence of pro-embryoid or not were evaluated. The combinations of regulators 2 mg L-1 2,4-D + 2 mg L -1 BAP, 2 mg L-1 Kinetin + 1 mg L-1 2,4-D, 2 mg L-1 2,4-D + 0.5 mg L-1 TDZ e 2 mg L-1 2,4-D induced callus formation. Callosity was favored after 60 days of in vitro cultivation. The combinations 2 mgL-1 2,4-D + 2 mgL-1 BAP, 2 mgL-1 Kinetin + 1 mgL-1 2,4-D, 2 mgL-1 2,4-D + 0.5 mgL-1 TDZ induced pro-embryoid formation.